Dimethylformamide → 2,3-Dichloro-6-fluorobenzaldehyde

Temperatur

-45 °C

A solution of 1.3M s-butyl lithium in cyclohexane (244 mL, 317 mmol) is added to a dry-ice/acetone cooled solution of TMEDA (34 g, 293 mmol) in THF (250 mL), maintaining the internal reaction temperature <-70° C. The resulting reaction mixture is cooled and maintained at ≤-90° C. with an ether/liquid nitrogen bath while a solution of 1,2-dichloro-4-fluorobenzene (40 g, 244 mmol) in THF (100 mL) is added dropwise. The resulting reaction mixture is stirred with dry-ice/acetone cooling for 1h, then is cannulated into an ether/liquid nitrogen cooled and mechanically stirred solution of DMF (89.1 g, 1.22 mol) in THF (125 mL). The resulting mixture is warmed to -45° C. and partitioned between dilute aqueous HCl and ether. The organic solution is washed with aqueous NaHCO3, dried (MgSO4), and concentrated to afford 44.38 g of 2-fluoro-5,6-dichlorobenzaldehyde as an oil.

1. temperaturemaintaining the internal reaction temperature <-70° C
2. customThe resulting reaction mixture
3. temperatureis cooled
4. additionis added dropwise
5. customThe resulting reaction mixture
6. temperaturecooled
7. custompartitioned between dilute aqueous HCl and ether
8. washThe organic solution is washed with aqueous NaHCO3
9. dry with materialdried (MgSO4)
10. concentrationconcentrated

ORD-Eintrag

ord-c71469b9738f4ef7aae2f3a53f0962d6

Quelldatensatz

uspto-grants-1996_01

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US05482974